Proposals have been made to repair a cracked rotor by cutting the rotor in the vicinity of the crack and then in getting rid of the cracked portion and in replacing said portion by a replacement part which is welded to the two parts of the rotor. However, this method presents difficulties, in particular for accurately aligning the two parts of the rotor.
In order to repair the rotor, the inventors have thought of machining a groove at the location of the crack in order to make the crack disappear, with the groove being of constant depth and going all the way round the rotor.